The present invention relates generally to a vehicle hood that is deployable upwardly in response to the vehicle impacting a pedestrian to provide additional crush space between the hood and underhood components, and more specifically to a hinge permitting normal opening and closing of the hood prior to deployment and that securely restrains the hood against rearward movement when in the deployed condition.
In modern automotive design it is desirable for visibility, aerodynamic and styling reasons that the hood line be kept as low as possible. As a result, there is generally very little clearance between the hood and the engine bay contents of the automotive vehicle. As a result, the hood is unable to yield enough to provide significant cushioning when a pedestrian strikes the hood during an accident. Pedestrian safety performance can be improved by increasing the clearance between the hood and the vehicle components beneath the hood.
One way to achieve a greater clearance while maintaining a low hood line during normal vehicle operations is to provide a device to raise the hood in response to or immediately prior to the vehicle impacting a pedestrian.
U.S. Pat. No. 6,217,108 and U.S. Pat. No. 6,1 82,782 disclose systems for raising the trailing edge of a vehicle hood. These systems utilize complicated, multi-part hinge mechanisms that are relatively expensive to manufacture and complicated to install in a vehicle.
The present invention provides a hood deployment device for an automotive vehicle having a body structure and a hood with a trailing edge and a leading edge, the device comprising a pivot secured to the body structure and having a first section of a first diameter, and a hinge secured to the hood. A slot is formed in the hinge and comprises a pivot retention pocket at an upper end of the slot having a width larger than the pivot diameter, a neck portion immediately below the pivot retention pocket having a width smaller than the pivot diameter, and a slide portion below the neck portion having a width larger than the pivot diameter.
During normal vehicle operation, the pivot has a normal position wherein the pivot engages the pivot retention pocket to permit rotating movement of the hinge and the hood about the pivot in order to open and close the hood. The narrowing of the slot at the neck portion prevents the hood from being lifted upwardly.
The hood deployment device further comprises a powered device disposed on the body structure and operable to urge the hinge and the hood upward relative to the body structure to a raised position, the pivot sliding downward toward a bottom of the slot as the hinge moves to the raised position. The powered device is activated upon detection or prediction of a collision with a pedestrian, and applies sufficient upward force to hood and/or hinge to force the pivot through the neck portion of the slot, the hinge and/or pivot deforming to allow the pivot to pass through. When in the raised position, the engagement of the pivot with the bottom of the slot provides mechanical resistance to rearward movement of the hood, such as may be caused by the collision of the pedestrian with the hood. The device has a minimum number of moving parts and so is inexpensive to manufacture. The invention hood deployment device is able to yield when in the deployed condition so as to absorb impact energy.
According to another feature of the invention, the slot further comprises an enlarged portion adjacent the bottom of the slide portion and of a width greater than the width of the slide portion, and the pivot further comprises an enlarged section axially adjacent to the first section. The enlarged section has a second diameter greater than the first diameter, smaller than the width of the enlarged portion, and greater than the width of the slide portion of the slot. When the hinge reaches the raised position the hinge is movable relative to the pivot in a lateral direction parallel to an axis of the pivot to place the enlarged section in engagement with the slot. The engagement between the enlarged section and the slide portion of the slot constitutes an interference fit that provides resistance to movement of the hinge and hood downward toward the normal position. The degree of resistance may be adjusted by proper selection of the second diameter relative to the width of the slide portion of the slot, so that movement of the hood downwardly from the raised position absorbs energy and so cushions the impact of the pedestrian with the hood.
Other features and advantages of the present invention will be readily appreciated and better understood after reading the subsequent description when considered in connection with the accompanying drawings.